Vat dyestuffs



2,861,073 VAT DYESTUFFS Wilhelm Eckert and Otto Fuchs Frankfurt am Main, Ger- 7 man assignors to Farbwerke Hoechst Aktiengesellschaft vormals Meister Lu'cius & Briining, Frankfurt 'am' Main, Germany, a corporationof Germany Application December 26, 1956, Serial'No.630,,457

Claims priority, application Germany January 4, 1956 i 5. Claims. (Cl. 260-272) a I N Drawing,

The present invention relates to valuable new vat dyestuffs, more particularly it relates to dyestuffs corresponding to the following general formula 0 R ll l wherein R represents hydrogen, an alkoxy, a benzoylwherein R and R represent substituted or unsubstituted aryl radicals which are different from each other. Insofar as mixtures of isomeric compounds are present, they can be separated from each other, for example, by the processes described in German Patent No. 536,911 or United States Patent 5 and 607,945.

All these dyestutfs have a pronounced aflinity for vegetable fibers, furthermore, a good fastness to washing and to chlorine and a very good fastness to light, but their fastness to boiling soda is in many cases insufiicient. Moreover, it is not possible to convert these dyestuffs into their leuco sulfuric acid esters according to the numerous processes hitherto known.-

The present invention provides new vat dyestuffs which meet high demands with regard to the fastness to boiling soda and which can be converted by various methods into their sulfuric acid esters through their leuco compounds; these vat dyestuffs can be obtained by condensing at higher temperatures naphthoylene-aryl- (or alkylaryl-) imidazole-peri-dicarboxylic acids or the anhydrides thereof with substituted or unsubstituted 1,2-diamino-anthraquinones in the presence of organic solvents or diluents or in an aqueous suspension. As 1,2-diamino-anthraquinones :there can advantageously be used in the process of this. in vention compounds corresponding to the following gen- V eral formula:

wherein R represents hydrogen, an alkoxy, a benzoy l f amino, chlorobenzoylamino or fluorob'enzoy'lamino group. 'l,

The naphthoylene-aryl- (or alkylar1yl-) imidazole-perifdicarboxylic acids or the anhydrides' thereof can also bieif condensed with l-nitro-Z-aminoor l-amino-Z-nitroanthraquinones and then treated at higher temperatures with reducing agents. By this treatment ring closure occurs with formation of imidazole derivatives. Furthertures.

The new dyestuifs are distinguished by a great colouring strength, p Y

Thefollowing examples serve to illustrate theinvention; but they are not intended to limit it thereto, the parts 3 gbeing byweight, unless otherwise stated and the relation-.

ship of parts by weightto parts by volume beingthe same asth at of the'kilogram to the liter. x

Example 1 340 parts of naphthoylene-benzimidaroleperi-dicarboxylicfanhydride and250 parts of 1,2-diaminoanthraquin'one are heated for about 1-5 hours at 210 .Cflwith 3000 parts of trichlorobenzene. After cooling to 150 C., the reaction product 'is filtered oif with suction and ,the

residue is washed with 2000 parts of hot trichlorobenzene. The adhering solvent is removed with methanol or ethanol 1 andthepiess cake is dried. In this manner a deep dark brown, crystalline-pigment is obtained.with avery.-g0od. yield; it dye's cotton froma redbrown vat a clear copper shade. The dyestutf hasa very'good fastness' to wash Patented Nov; 18-, 1. .8;

ing, to chlorine, to boiling soda and to light.

It corresponds to the following formula Example 2 I 38 parts of naphthoylene-benzimidazole-peri dicarboxylic anhydride and 40 parts of 1,2-diamino-4-benzoyl: aminoanthraquinone are heated at the boil for 15 hours in 380 parts of trichlorobenzene. The reaction product is worked up as described in Example 1. The dyestutf so obtained dyes cotton from a red-brown vat bluish redbrown tints of very good fastness properties.

Example 3 Example 4 20 parts of naphthoylene-4'-ethoxy-benzimidazole-peridicarboxylic anhydride and 10 parts of 1,2-diaminoanthraquinone are heated under reflux for 6 hours with 150 parts of quinoline. The reaction product is worked up as described in Example 3. The dyestuff is obtained with a good yield. It dyes cotton from a red-brown vat deep dark-brown tints.

Example 20 parts of the dyestufi described in Example 4 and 15 parts of copper powder are introduced at 35 C. into an esterification mixture prepared at 2025 C. from 200 parts of a-picoline and 40 parts of chlorosulfonic acid. The. mixture is stirred for one hour at 45 C. and the resulting dark mass is then added to a mixture of 500' parts of water, 500 parts of ice and 10 parts of kieselguhr. The dark precipitate is filtered off with suction, washed with cold water and introduced into a solution of 40 parts of caustic soda in 1000 parts of water. The a-picoline is removed by distillation under reduced pressure and the solution of the ester is clarified by filtration. The clear brown solution of the leuco sulfuric acid ester is salted out with sodium chloride.

cotton. viscose rayon and staple fibers of regenerated cellulose by the known dyeing processes dark brown tints which correspond to the original dyestufi and exhibit the same very good fastness properties.

The ester, which has, been dried and stabilized by the addition of soda, dyes Example 6 100 parts of naphthoylene-benzimidazole-peri-dicarboxylic anhydride are heated at the boil for 20 hours with 115 parts of 1,2-diamino-4-(4'-chlorobenzoylamino)-anthraquinone in 1000 parts by volume of trichlorobenzene while continuously distilling oil the reaction water. The condensation product is workedup as described in Example 1. The dyestuff so obtained dyes cotton from a brown vat full red-brown tints of very good fastness properties.

Example 7 50 parts of naphthoylene-benzimidazole-peri-dicarboxylic anhydride and parts of 1,2-diamino-4-(2-fluorobenzoylamino)-anthraquinone are heated at the boil for 20 hours in 1000 parts by volume of a-chloronaphthalene. The condensation product is worked up as described in Example 1. A red-brown pigment is obtained which dyes cotton from a brown vat full bluish red-brown tints of very good fastness properties.

We claim:

1. The vat dyestuffs corresponding to the following general formula wherein R represents a member selected from the group consisting of hydrogen, benzoylamino, 4-chlorobenzoylamino and 2-fiuorobenzoylamino, and R represents a member selected from the group consisting of phenylene, chlorophenylene and ethoxyphenylene.

2. The vat dyestuff corresponding to the following formula 3. The vat dyestuff corresponding to the following formula NH-O O f vat dyestufi corresponding to the following References Cited inthe file of this patent arm a UNITED STATES PATENTS (I) NH-C O 

1. THE VAT DYESTUFF CORRESPONDING TO THE FOLLOWING GENERAL FORMULA 